Negative pressure wound therapy system and a feedback control method for the same

ABSTRACT

A negative pressure wound therapy system creates a negative pressure environment in the opening of a wound-dressing unit and a positive pressure environment in the collecting bag. Then a positive pressure detecting procedure is proceeded in the positive pressure environment and a negative pressure detecting procedure is proceeded in the negative pressure environment. The detecting results are sent to determine whether a micro pump is stopped.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a negative pressure wound therapysystem and a feedback control method for the same, especially to atherapy system creating negative pressure in the wound environment topromote healing in wounds.

2. Description of the Prior Arts

Negative pressure wound therapy utilizes wound sheets, soft suctionpads, or biocompatibility pore materials to attach on the wounds andconnects to a vacuum pump. The vacuum pump creates negative pressure inthe wound to extract the pus and infection subjects and to draw thehealthy tissue fluid so that a moist therapy environment is maintained.Therefore, the blood circulation around the wound is promoted toaccelerate wound healing.

One of the conventional negative pressure wound therapy systems has arigid collector connecting to a front end of the vacuum pump to extractthe pus and the infection subjects into the rigid collector. A negativepressure sensor detects the negative pressure in the collector todetermine whether the traditional system is operated normally. However,since the vacuum pump is connected to the rear end of the rigidcollector, the pump is further from the wound so that the pump needsmore power to create negative pressure in the wound and to extract thepus and the infection subjects from the wound.

Another conventional negative pressure wound therapy system solves theabove problem. The collector is connected to the rear end of the vacuumpump. The vacuum pump is directly connected to the wound sheet attachedon the wound so that the vacuum pump uses less power. However, thecollector does not have the same negative pressure environment as thewound. Therefore, the negative pressure sensor is not useful to detect.

To overcome the shortcomings, the present invention provides a negativepressure wound therapy system and a feedback control method for the sameto mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a negativepressure wound therapy system and a feedback control method for thesame. The system creates a negative pressure environment in the openingof a wound-dressing unit and a positive pressure environment in thecollecting bag. Then a positive pressure detecting procedure isproceeded in the positive pressure environment and a negative pressuredetecting procedure is proceeded in the negative pressure environment.The detecting results are sent to determine whether a micro pump isstopped.

Other objectives, advantages and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a negative pressure wound therapy systemin accordance with the present invention;

FIG. 2 is a block diagram shown the connection of the negative pressurewound therapy system in FIG. 1;

FIG. 3 is a perspective view of a wound-dressing unit of the negativepressure wound therapy system;

FIG. 4 is an exploded perspective view of the negative pressure woundtherapy system in FIG. 1;

FIG. 5 is an exploded perspective view of a sensor assembly and anactuator of the negative pressure wound therapy system in FIG. 1;

FIG. 6 is a partial perspective view of the actuator of the negativepressure wound therapy system in FIG. 1;

FIG. 7 is a flow chart shown test mode of a feedback control method inaccordance with the present invention for the negative pressure woundtherapy system in FIG. 1; and

FIG. 8 is a flow chart shown operating mode of the feedback controlmethod for the negative pressure wound therapy system in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, a negative pressure wound therapy system inaccordance with the present invention comprises a controller 10, asensor assembly 20, an actuator 30, a collector 40 and a wound-dressingunit 50.

With reference to FIGS. 1 and 2, the controller 10 comprises amicroprocessor 11, a power supply unit 12 and a control panel 13. Thepower supply unit 12 electrically connects to the microprocessor 11,provides electricity and may be a battery set, or may be a powerconverter connected to an external power source. The control panel 13 isattached to an outer surface of the controller 10 and electricallyconnects to the microprocessor 11 and the power supply unit 12.

The sensor assembly 20 comprises a negative pressure sensor 21, apositive pressure sensor 22 and a relief valve 23. The relief valve 23adjusts the pressure of the system and may apply an intermittent mode.

The actuator 30 comprises a micro pump 31.

The collector 40 comprises a collecting bag 41 and a liquid absorber 42.The liquid absorber 42 is mounted in the collecting bag 41.

With reference to FIG. 3, the wound-dressing unit 50 comprises a woundsheet 51 and a conduit 52. The wound sheet 51 has an opening 511. Theconduit 52 is attached securely to the wound sheet 51 and is connectedto the opening 511 and has a filter strip 521. The filter strip 521 ismade of biocompatibility materials and keeps solid chips such as tissuefragment from flowing into the conduit 52. In a preferred embodiment,the conduit 52 is attached securely to the wound sheet 51 by ultrasonicwelding.

With reference to FIGS. 2 and 4, the negative pressure wound therapysystem in accordance with the present invention comprises electricalconnection and fluid connection to connect aforementioned elements.

The controller 10 is electrically connected to the sensor assembly 20,and the sensor assembly 20 is electrically connected to the actuator 30.Detachable electrical wire set forms the electrical connection. Forexample, an electrical wire 61 with a plug 62 protrudes out from thesensor assembly 20. The controller 10 has a corresponding socket 63. Theplug 62 is plugged detachably into the socket 63 to form the electricalconnection.

A fluid connection is formed between the pump inlet 311 of the micropump 31 and the conduit 52. A fluid connection is formed between thepump outlet 312 of the micro pump 31 and the entry end of the collectingbag 41. A check valve is mounted in the entry end 411 of the collectingbag 41 to keep the liquid in the collecting bag 41 from flowing back toinfect the wound. Detachable fluid tube set forms the fluid connections.For example, a first tube 64 with a fluid connector 65 protrudes outfrom the micro pump 31 and a second tube 64 with a fluid connector 65protrudes out from the conduit 52. The fluid connectors 65 detachablyconnect to each other to form the fluid connection.

A fluid connection is formed between the positive pressure sensor 22 andthe detecting end 412 of the collecting bag 41. A fluid connection isformed between the negative pressure sensor 21, the relief valve 23 andthe conduit 52, especially through the pump inlet 311 of the micro pump31. Detachable tube set forms the fluid connections. For example, a tube64 with a first fluid connector 65 protrudes out from the positivepressure sensor 22. A second fluid connector 65 is mounted on thedetecting end 412 of the collecting bag 41. The fluid connectors 65detachably connect to each other to form the fluid connection.

With reference to FIGS. 5 and 6, in a preferred embodiment the sensorassembly 20 has a first connecting interface 201, and the actuator 30has a second connecting interface 301. The first connecting interface201 has a first electrical connector 202 and a first fluid connector203. The second connecting interface 301 has a second electricalconnector 302 and a second fluid connector 303. The micro pump 31 iselectrically connected to the second electrical connector 302. Theconnecting interfaces 201, 301 are connected detachably to each other.The first electrical connector 202 is connected to the second electricalconnector 302. The first fluid connector 203 is connected to the secondfluid connector 303. A fluid division 66 may be a manifold and comprisesa first passage 661 and a second passage 662. The first passage 661connects the pump inlet 311 of the micro pump 31 and the conduit 52. Thesecond passage 662 connects the second fluid connector 303 and theconduit 52.

Furthermore, filters 70 are mounted in the detecting end 412 of thecollecting bag 41 and the second fluid connector 303 of the actuator 30to keep the infections from flowing into the sensor assembly 20.

With the aforementioned electrical connections and the fluid connectionsbeing detachably, the elements are available to detach from each otherto be repaired independently.

When the system as described is operated, the wound sheet 51 covers thewound of the patient with the opening 511 facing the wound. The useractuates the micro pump 31 through the control panel 13. The micro pump31 creates a negative pressure environment in the wound through thefluid connections and extracts the pus and infection subjects from thewound. The pus and infection subjects pass through the actuator 30 andare collected in the collecting bag 41.

The system as described has following advantages.

1. Since all of the components connect to each other by detachableelectrical wire sets and detachable tube sets, each component isavailable to be disassembled and repaired independently.

2. The components have different lifespan. For example, the collector 40and the wound-dressing unit 50 directly contact the infections so thatthe collector 40 and the wound-dressing unit 50 need to be replacedfrequently while the controller 10, the actuator 30 and the sensorassembly 20 can be used for a long time. Therefore, the detachableconnections are convenient for users to disassemble and replace eachcomponent.

3. When the user moves between different places such as hospital andhome, the detachable connections allow the user only bring some of thecomponents to move. For example, the user only carries the controller10, the sensor assembly 20 and the actuator 30, and leaves thecollectors 40 and the wound-dressing units 50 at different places, andvice versa. Therefore, the user only needs to carry part of the system.

4. In the fluid connections, the actuator 30 is located in front of thecollecting bag 41. The micro pump 31 is directly connected to the woundsheet attached on the wound so that the micro pump uses less power.

To ensure the system as described is operated safely, a feedback controlmethod in accordance with the present invention for the system asdescribed comprises a test mode and an operating mode.

With reference to FIG. 7, when the system as described is started, thesystem enters the test mode. The micro pump 31 inflates the fluidconnections in the system. Then the positive pressure sensor 22 detectswhether the positive pressure at the detecting end 412 of the collectingbag 41 is normal. When the fluid connections are not connected properly,the positive pressure is abnormal. If the positive pressure is abnormal,the system outputs an alarm signal. Then the test mode is ended. Whenthe fluid connections are connected properly, the positive pressure isnormal. If the positive pressure is normal, the system enters theoperating mode.

With reference to FIG. 8, when the system enters the operating mode, themicro pump 31 creates a negative pressure environment in the woundthrough the opening 511 of the wound sheet 51 and extracts the pus andinfection subjects from the wound. Then the collecting bag 41 isaccordingly formed as a positive pressure environment. Then the positivepressure detecting procedure and negative pressure detecting procedureare started.

The positive pressure detecting procedure detects the positive pressurein the collecting bag 41. The positive pressure sensor 22 detectswhether the positive pressure in the collecting bag 41 is normal. Whenthe fluid connections between the collecting bag 41 and other elementsare disconnected, or an external overload is applied to the collectingbag 41, or the collecting bag 41 is full of liquid, the positivepressure of the detecting end 412 of the collecting bag 41 is abnormal.If the positive pressure is abnormal, the positive pressure sensor 22sends a signal to the microprocessor 11 to stop the micro pump 31 andsend an alarm signal to notify the user. Therefore, the pus and theinfection subjects are prevented from leaking out of the fluidconnections or the collecting bag 41 is prevented from breaking becauseof overload or being full. Then the operating mode is ended. If thepositive pressure is normal, the positive pressure sensor 22 keepsprocessing the positive pressure detecting procedure.

The negative pressure detecting procedure detects the negative pressurein the wound. The negative pressure sensor 21 detects whether thenegative pressure in the opening 511 of the wound sheet 51 is normal.When the fluid connections is obstructed or is disconnected, thenegative pressure is abnormal. If the negative pressure is abnormal, thenegative pressure sensor 21 sends a signal to the microprocessor 11 tostop the micro pump 31 and send an alarm signal to notify the user. Ifthe negative pressure is normal, the negative pressure sensor 23 keepsprocessing the positive pressure detecting procedure.

With the aforementioned modes, the system as described is operatedsafely.

Even though numerous characteristics and advantages of the presentinvention have been set forth in the foregoing description, togetherwith details of the structure and features of the invention, thedisclosure is illustrative only. Changes may be made in the details,especially in matters of shape, size, and arrangement of parts withinthe principles of the invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed.

What is claimed is:
 1. A feedback control method for a negative pressure wound therapy system that the system has a wound-dressing unit and a collecting bag communicating with the wound-dressing unit, the method comprising an operating mode, which comprises acts of: (a) creating a negative pressure environment in an opening of a wound-dressing unit and a positive pressure environment in the collecting bag; (b) proceeding a positive pressure detecting procedure in the positive pressure environment and proceeding a negative pressure detecting procedure in the negative pressure environment; and (c) sending the detecting results to determine whether the operating mode is ended.
 2. The feedback control method as claimed in claim 1, wherein before step (a) further comprises an act of applying a micro pump between the wound-dressing unit and the collecting bag to creating the negative pressure environment and extracting the fluid in the opening.
 3. The feedback control method as claimed in claim 2, wherein positive pressure detecting procedure further comprises acts of: detecting the positive pressure in a detecting end of the collecting bag by a positive pressure sensor; and determining whether the positive pressure is normal; if the positive pressure is abnormal, the micro pump is stopped and the operating mode is ended; if the positive pressure is normal, the micro pump is kept operating and back to the act of the detecting positive pressure.
 4. The feedback control method as claimed in claim 2, wherein negative pressure detecting procedure further comprises acts of: detecting the negative pressure in the opening of the wound-dressing unit by a negative pressure sensor; and determining whether the negative pressure is normal; if the negative pressure is abnormal, the micro pump is stopped and the operating mode is ended; if the negative pressure is normal, the micro pump is kept operating and back to the act of the detecting negative pressure.
 5. The feedback control method as claimed in claim 3, wherein negative pressure detecting procedure further comprises acts of: detecting the negative pressure in the opening of the wound-dressing unit by a negative pressure sensor; and determining whether the negative pressure is normal; if the negative pressure is abnormal, the micro pump is stopped and the operating mode is ended; if the negative pressure is normal, the micro pump is kept operating and back to the act of the detecting negative pressure.
 6. The feedback control method as claimed in claim 2 further comprising a test mode before proceeding the operating mode, wherein the test mode comprises acts of: inflating fluid connections in the system by the micro pump; detecting the positive pressure in a detecting end of the collecting bag by a positive pressure sensor; and determining whether the positive pressure is normal; if the positive pressure is abnormal, an alarm signal is output and the test mode is ended; if the positive pressure is normal, the test mode is end and the operating mode is entered.
 7. The feedback control method as claimed in claim 3 further comprising a test mode before proceeding the operating mode, wherein the test mode comprises acts of: inflating fluid connections in the system by the micro pump; detecting the positive pressure in the detecting end of the collecting bag by the positive pressure sensor; and determining whether the positive pressure is normal; if the positive pressure is abnormal, an alarm signal is output and the test mode is ended; if the positive pressure is normal, the test mode is end and the operating mode is entered.
 8. The feedback control method as claimed in claim 4 further comprising a test mode before proceeding the operating mode, wherein the test mode comprises acts of: inflating fluid connections in the system by the micro pump; detecting the positive pressure in the detecting end of the collecting bag by the positive pressure sensor; and determining whether the positive pressure is normal; if the positive pressure is abnormal, an alarm signal is output and the test mode is ended; if the positive pressure is normal, the test mode is end and the operating mode is entered.
 9. The feedback control method as claimed in claim 5 further comprising a test mode before proceeding the operating mode, wherein the test mode comprises acts of: inflating fluid connections in the system by the micro pump; detecting the positive pressure in the detecting end of the collecting bag by the positive pressure sensor; and determining whether the positive pressure is normal; if the positive pressure is abnormal, an alarm signal is output and the test mode is ended; if the positive pressure is normal, the test mode is end and the operating mode is entered.
 10. A negative pressure wound therapy system comprising: a controller; a sensor assembly electrically connected to the controller and comprising a negative pressure sensor and a positive pressure sensor to detect pressure, and comprising a relief valve; an actuator comprising a micro pump electrically connected to the sensor assembly; a collector comprising a collecting bag; a wound-dressing unit having an opening; a first fluid connection connecting between the sensor assembly and the collecting bag; a second fluid connection connecting between the sensor assembly and the wound-dressing unit; a third fluid connection connecting between the wound-dressing unit, the actuator and the collecting bag, wherein the actuator is located between the wound-dressing unit and the collecting bag in the third fluid connection; whereby the micro pump creates a negative pressure environment in the opening through the third fluid connection and extracts the fluid from the opening of the wound-dressing unit, and the fluid passes the actuator to flow into the collecting bag, and the collecting bag is defined as a positive pressure environment.
 11. The negative pressure wound therapy system as claimed in claim 10 further comprising: a first detachable electrical wire set connecting between the sensor assembly and the controller; a second detachable electrical wire set connecting between the sensor assembly and the micro pump; a first detachable tube set connecting between a pump inlet of the micro pump and the sensor assembly; a second detachable tube set connecting between a detecting end of the collecting bag and the sensor assembly; a third detachable tube set connecting between an inlet end of the collecting bag and a pump outlet of the micro pump; a fourth detachable tube set connecting between the wound-dressing unit and the sensor assembly; and a fifth detachable tube set connecting between the wound-dressing unit and the pump inlet of the micro pump, wherein the first fluid connection is formed by the second detachable tube set; the second fluid connection is formed by the fourth detachable tube set; and the third fluid connection is formed by the first, third and fifth detachable tube sets.
 12. The negative pressure wound therapy system as claimed in claim 11, wherein the wound-dressing unit comprises a wound sheet, where the opening of the wound-dressing unit is formed through; and a conduit attached securely to the wound sheet, connected to the opening and having a filter strip made of biocompatibility materials; the fourth detachable tube set connects between the conduit and the negative pressure sensor and the relief valve; and the fifth detachable tube set connects between the conduit and the pump inlet of the micro pump.
 13. The negative pressure wound therapy system as claimed in claim 12 further comprising a fluid division, wherein the sensor assembly has a first connecting interface having a first electrical connector and a first fluid connector; and the actuator has a second connecting interface connected detachably to the first connecting interface and having a second electrical connector electrically connected to the micro pump connected to the first electrical connector; and a second fluid connector connected to the first fluid connector; the fluid division comprises a first passage connecting the pump inlet of the micro pump and the conduit; and a second passage connecting the second fluid connector and the conduit.
 14. The negative pressure wound therapy system as claimed in claim 12, wherein the fifth detachable tube set comprises a first tube with a fluid connector protruding out from the micro pump and a second tube with a fluid connector protruding out from the conduit, and the fluid connectors detachably connect to each other.
 15. The negative pressure wound therapy system as claimed in claim 13, wherein the fifth detachable tube set comprises a first tube with a fluid connector protruding out from the micro pump and a second tube with a fluid connector protruding out from the conduit, and the fluid connectors detachably connect to each other.
 16. The negative pressure wound therapy system as claimed in claim 15, wherein the second detachable tube set comprises a tube with a first fluid connector protruding out from the positive pressure sensor and a second fluid connector mounted on the detecting end of the collecting bag, and the fluid connectors detachably connect to each other.
 17. The negative pressure wound therapy system as claimed in claim 16 further comprising two filters respectively mounted in the detecting end of the collecting bag and the second fluid connector of the actuator to keep the infections from flowing into the sensor assembly.
 18. The negative pressure wound therapy system as claimed in claim 17 further comprising check valve mounted in an entry end of the collecting bag to keep the liquid in the collecting bag from flowing back. 